maybe, but I doubt a mechanic would send you all the way to a junkyard just for that one - hell, you could just about use a one-foot section of garden hose to fix it!
The other one (the PCV tube) has a crazy geometry because it snakes around the engine and thus is more expensive; so, based on his junkyard suggestion, that might have been what he was referring to. A crack in that one can affect idle, but it's harder to locate, inspect, and replace.
If he's gonna do the work for you, you probably have enuf information at this point to take it back to him and discuss the PCV tube & IAC, maybe print out this thread.
"I'm jealous of girls because they get to wear dresses." (Todd Flanders)